In modern poultry processing methods and facilities, a given bird is subjected to numerous sequential operations. Typically, the bird is passed through a slaughtering line where it is bled and plucked to produce a raw carcass. Thereafter the carcass is passed through an evisceration room where the giblets are removed. The eviscerated carcass is placed in a chiller and thereafter hung on a drip line or sizing line. The sizing line typically includes an overhead conveyor having a series of trolleys mounted thereon. The trolleys each have a shackle depending therefrom. The birds are removably mounted on the shackles by inserting the legs into the shackles.
Usually, some form of cutting or further processing will add more value to a given poultry carcass than if the carcass were sold as a whole. In order to realize more value from the birds, after the birds have been placed on the sizing line and quality graded, they are sorted by weight and grade and are distributed into various processing steps including cutting, deboning, and solution injections. This type of processing can be very labor intensive. As discussed below, the overall profitability of the process is a function of the yield gained from each pound of processed meat which, in turn, is directly related to accurately matching bird weight with the operations to be performed.
Birds taken from the chiller are hung on a sizing line where they are weighed and sorted by weight and quality grade. The largest birds are typically sent to cut-up departments in order to maximize the total weight processed in these operations (i.e., to maximize yield). Today, these birds are dropped off of the sizing line and must be re-hung onto another line or cut-up machine. Special sizes selected by weight for fast food restaurant operations are usually processed on automatic machines that are set up for specific weight ranges of products. The remaining birds are sent to other operations.
Total plant yield is becoming an increasingly critical measurement for processing plants due to higher production costs and decreased margins. Each flock of birds being processed has birds of different weights throughout a range, and different flocks have different weight distributions. Some plants cannot justify the additional labor that is required to hang all of the birds exiting the chiller onto the sizing line, where they can be sorted by weight and grade. In these operations, birds are hung directly on the cut-up line in sufficient quantity to keep each cut-up shackle full, and hence to maximize the throughput of the department. Since there is no method available today to weigh on these cut-up lines, the total weight of products sent to the cut-up department remains "unknown" and total plant yield cannot be calculated.
Most of today's cut-up lines are automated lines. Birds are hung on shackles with both legs in order to orient the breast in the same direction. Although there are several types of cut-up machines, one of the most popular type splits off the breast and leaves the leg quarters riding in the shackle to pass into another machine. The breasts (front halves) are manually inserted into one of several special machines designed to separate the valuable meat from the bone. This deboning process can be optimized when the weight of each bird is accurately determined. The blades of the machines can be adjusted more accurately and the overall yield of the operation can be substantially improved.
In more sophisticated plants, in fast food plants, for example, each bird is hung on a shackle of a sizing line and each shackle (and thus the bird mounted on the shackle) is tracked by computer. The shackle with the bird thereon is weighed along the conveyor to determine the weight of the bird. Based on the weight of the bird, the preprogrammed computer determines the appropriate use for the bird. For example, birds in a given weight range may be targeted for sale to fast food restaurant A, birds in a second weight range may be targeted for sale to fast food restaurant B, and birds outside of these weight ranges may be targeted for ice packing. The computer controls drops along the conveyor so that the birds falling within a prescribed weight range are dropped at the stations at which they are to be processed.
It is very important that the birds be accurately weighed. Birds processed and sold to fast food restaurants and the like are sold at a premium. However, only birds which clearly fall within the prescribed weight ranges are acceptable. Birds which do not fall within the desired weight ranges may be suitable only for ice packing or the like, in which case they demand only a relatively low price. Accordingly, it is important that all birds which fall within the prescribed premium ranges are identified so that they are not inadvertently directed to the less profitable ice packing process. Because assurance must be provided that birds directed to the premium processes are in fact of appropriate weight, margins of error are observed in identifying the weights of birds so that any inaccuracy in weighing does not result in an overweight or underweight bird being sent to a premium process. If a suitable bird falls within the margin of error, it will be directed to a less profitable use than it could properly be used for. Similarly, if a bird of appropriate weight is inaccurately weighed and identified as out of the premium weight range, it will be directed to the less profitable use nonetheless. Thus, increasing the accuracy of weighing the birds is key to optimizing the usage of the birds and maximizing the profitability of the operation.
As a practical matter, the accuracy of weighing the birds decreases substantially linearly with increase in the speed of the sizing line. Unless the line is slowed from its maximum rate, wide margins of error must be observed, resulting in substantial waste of premium weight birds. In particular, the faster the line is run, the more the birds tend to swing, oscillate, wobble and bump adjacent birds, substantially decreasing the ability of the scale to accurately weigh the birds. Wear, friction, and damage to the conveyor and the shackles also decrease accuracy.
Another problem commonly experienced in poultry processing plants is difficulty in positioning and holding the suspended bird for cutting operations. Conventional shackles and trolleys typically allow the shackle to which the bird is mounted to swing in one or more vertical planes. Therefore, sizing shackles are not and cannot be used for cut-up operations.
Thus, there exists a need for a means and a method for increasing the accuracy with which birds suspended from a conveyor may be weighed. Moreover, there exists a need for a means and method for stabilizing a bird on a cut up line to provide more cost effective, accurate and efficient cutting of the bird. There exists a need for a means and method which provides for both accurate weighing and cutting at high speeds without requiring that the bird be transferred from one holding device to another holding device.